TM-9-2350-311-20-2
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS
DECEMBER 1993
TM-9-2350-311-20-2 - Page 49 of 828
TM 9–2350–311–20–2
1–18
1–15 DIFFERENCES BETWEEN MODELS — CONTINUED
Functional group and part
Number of Variations
How assemblies/parts differ
02
Mount, howitzer
2
M109A2/M109A3/M109A4 howit-
zers have M178 mount. M109A5
howitzers have M182 mount.
Mounts are similar in maintenance
characteristics, although there are
subtle differences in parts. Refer to
TM 9–2350–311–24P–2 for specific
part number changes.
An access plate has been added to
the cradle of M109A5 howitzers.
03
Cab hydraulics
2
M109A4/M109A5 howitzers have a
hydroscopic breather and an air line
filter.
Clutch valve and attaching hoses
have been added to M109A4/M109A5
howitzers.
03
Power pack assembly
2
M109A4/M109A5 howitzers have
eliminated internal hydraulic filter of
M109A2 and M109A3 howitzers, re-
placing it with two external filters.
05
Power lead assembly
2
Number of leads is 3 or 5 depending
on number of contact arm assem-
blies in vehicle. An additional lead
for NBC control box was added to
M109A4/M109A5 howitzers.
05
NBC power lead assembly
2
M109A4/M109A5 howitzers have an
NBC power lead assembly.
05
Power relay box to intercom power supply
2
Number of leads differs. One har-
lead assembly
ness used for vehicles with 5 con-
tact arm assemblies; other harness
used for vehicles with 3 contact arm
assemblies.
06
Contact arm assemblies
2
Some M109A3 vehicles have 3 and
some vehicles have 5 contact arm
assemblies (slip ring brush holders).
M109A2/M109A4/M109A5 vehicles
have 5 contact arm assemblies.
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